The Danish government unveiled on Thursday its plan to impose a roughly $14 tax on air travel to help fund its aviation industry’s sustainability efforts.

Danish officials said roughly half of the expected annual proceeds of $172.3 million (1.2 billion krone) will go toward its aim of having domestic flights use only green fuels by 2030. The government plans to gradually phase in the passenger tax from 2025.

The tax will be roughly $9 for travel in Europe, $34 for medium-distance flights, and $56 for long-distance by 2030.

“The aviation sector in Denmark must – just like all other industries – reduce its climate footprint and move towards a green future,” said Danish Minister for Climate, Energy and Utilities Lars Aagaard.